The Latin word is natura, which, at first sight, seems less abstruse and metaphysical than the Greek οὐσία, or ὑπόστασις, or the Latin essentia and substantia, though it is not really so. A man’s natura, nature, is what he is at and from the beginning; “change of nature” means not an absolute change, but a reformation, a new guidance and treatment of tendencies, passions, powers—some receiving a precedence denied them before, others being suppressed and put in subjection. So God’s “nature” is what He is from and to all eternity, in Himself, unchangingly and unchangeably.